(Q2).A cylinder of radius 12 cm. contains water to a depth of 20 cm. A spherical iron ball is dropped into the cylinder and thus the level of water is raised by 6.75 cm. Find the radius of the ball. [π =
22
7
]

Rise in the water level is seen as a cylinder of radius ‘r’ = 12 cm

Height, h = 6.75 cm.

Volume of the rise = Volume of the spherical iron ball dropped

πr12h =
4
3
πr23
r12h =
4
3
r23
××cm3 =
×23 cm3
r23 =
×××

= × ×

= ×

=

r3 = × ×

= ( × ) × ( × ) × ( × )

∴ Radius of the ball r = cm.